Use of Luminescent Bacteria for Determining Toxicity in Aquatic Environments

A simple rapid method for monitoring the toxicity of aquatic samples has been developed. The assay is based on changes in the light output of luminescent bacteria, as measured in a photometric device. Under suitable conditions, selected strains of luminescent bacteria emit a constant amount of light as a metabolic by-product. On exposure to toxicants, the light intensity is quickly diminished by an amount which is proportional to the concentration of the toxicant. An initial comparison of this new method with a 96-h acute fish toxicity test suggests that the bacterial test compares favorably in sensitivity with other tests while being more simple and rapid to perform. Data can be obtained in two to five minutes. Some examples of demonstrated sensitivities (in mg/litre) are: pentachlorophenol, 0.005; carbon tetrachloride, 6.0; sodium lauryl sulfate, 1.0; chlordane, 0.6; and sodium hypochlorite, 0.005.